Nitrogen, carbon, hydrogen, oxygen, phosphorus and sulphur are some of the essential building blocks for all living beings. Grounds contain all of these elements in natural form, in addition to other macro and micronutrients which are needed for plant growth. Typically, such elements are not present in the ground in sufficient quantity or in forms that can maintain nutrition, growth and maximum yield of plants or crops. In order to overcome these deficiencies, fertilizers are often added to the ground with certain nutrients in amounts and specific ways, thereby enriching the growth medium either ground or substrate. With regard to nitrogen fertilization, plants can absorb nitrogen as ammonia or nitrate, both forms present in the ground but with dynamic and different benefits. Nitrogen, as any other nutrient, is force, yield and fruit quality determining. Inorganic nitrogen forms in the ground, and only the ammonium nitrate are of importance in agricultural nutrition. The ammonia fertilizer to be applied to the ground are subjected to the process of nitrification (nitrate in ammonia conversion) product of bacteria which are found naturally in grounds.
Under field conditions, nitrification proceeds very rapidly and the dominant form of nitrogen in ground is nitrate. From the plant and environmental point of view, ammonium nitrate is preferable regarding if it is available, but its nitrite and nitrate transformation is very fast. Once in the root, the ammonia passed directly to the amino acid form, but nitrate must be reduced (NO3−+8H++8e−→NH3+2H2O+OH−). When it is fertilized with an ammonia source and it is near the root, its absorption is very fast. Ammonium cause an increase in cytokinins hormones of plant and promotes more floral initiation than nitrate. However, the nitrate absorption stimulates the cations uptake, while the ammonia absorption inhibited this absorption.
Due to the ground dynamics of this nutrient it is susceptible to losses, which has a human health, environment and productivity impact. These losses are mainly produced by leaching, denitrification and volatilization. Leaching causes heavy pollution of ground and surface waters which causes in the environment an excessive algae growth in streams and health problems in humans such as gastric cancer and metahemoglobinemoa. Denitrification and volatilization cause an ozone increased (O3) in the troposphere (NO), reduced of the atmospheric visibility, increased the acid rain, O3 decreased in the stratosphear (N2O) and global warming.
The nitrate form nitrogen is very soluble and because of the nitrate ion negatively charged it cannot be absorbed into the clay-humic complex ground and it is lost through leaching. Nitrogen in the urea form, having no charge, while it does not transform is subjected to the same leaching process. Only the nitrogen in the form of ammonia, may be retained in the ground clay-humic complex. Therefore, search techniques that reduce nitrogen losses and make more efficiently the use of nitrogen fertilizers is one of the priority challenges of the fertilizer industry worldwide
There are tools and technologies that enable a more efficient and safe nitrogen use, they are aimed that in the moment of fertilizing settings that balance the plants requirements with fertilizer applications are applied, among them we found the fertilization splitting, fertigation, fertilization according to plant physiology, slow release fertilizers, and the use of inhibitors of processes, such as nitrogenous inhibitors.
The state of the art considers four types of products that make more efficient nitrogen fertilization
1. Slow and/or controlled release fertilizers, are fertilizers that containing a plant nutrient in a way that slows or dosed their availability and use after application, dosing for months the nutrients supply, reducing toxicity gradually through the slow delivery of salts and allowing the major part of the fertilizer without causing loss or phytotoxicity.
2. Slow dissolution and decomposition Molecules are urea condensation products and its aldehydes: Urea-formaldehyde (UF) 38% N; Urea-isobutyraldehyde (IBDU®) 32% N; Crotonyl diurea (CDU®) 32.5% N. The slow dissolution is due to the limited solubility of these products and the ground decomposition time up to absorbable forms for plants.
3. The Conventional coated fertilizers are fertilizers which are coated with a protective impermeable or semipermeable (Sulphur (SCU), synthetic polymers (PCF), organic materials (waxes) layer, which controls the release of nutrients rate.
4. Finally, inhibitors of urease and nitrification are compounds that inhibit bacterial action, slow down the urea to ammonia conversion and ammonium to nitrate, and decrease losses of N as leaching nitrate or by denitrification. Examples of these inhibitors are NBTPT urease inhibitor, Nitrapyrin nitrification inhibitor (use only in US), DCD nitrification inhibitor and DMPP nitrification inhibitor (more effective, better compatibility.
The DMPP delays the ammonium to nitrite bacterial oxidation, by inhibiting the action of the enzyme ammonia monooxygenase (AMO) nitrosomonas bacteria specific. It has a bacteriostatic not bactericidal effect, making their proliferation slower, producing a temporary increase of the ammonium in the ground at the expense of nitrate. Its advantages are: high-efficiency on Nitrosomonas bacteria inhibition, 4 to 10 weeks bacteriostatic effect, high selectivity since it only inhibits the Nitrosomonas bacteria, completely degrades in the ground, which is effective at very low doses, incorporating to all kinds of formulations, leaching minimal decreases, inhibits part of urea volatilization, it is non-toxic.